JPS6159469B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a nuclear reactor core support frame device.

In a nuclear reactor, such as a fast breeder reactor, the core is filled with high-temperature liquid sodium and contains several hundred core components each having a hexagonal cross section. Only the lower ends of these core components are supported and positioned on a support plate provided below the core, and the upper ends are free. In order to suppress deformation of the above-mentioned components due to heat or earthquakes, a core support frame is provided at the upper and intermediate portions of the component group so as to surround and bundle the component group. Therefore, the core components are cantilever beams with one end fixed and the other end free, and because they are closely arranged with small intervals in the hot fluid, they exhibit complex behavior during earthquakes. In particular, core components adjacent to the core support frame may be subjected to relatively large collision loads due to collisions with internal components and the support frame. Therefore, the core support frame not only minimizes deformation of the core components due to heat and earthquakes, but also reduces the collision force in the event of a collision with the core components, thereby improving the earthquake resistance of the core components. It is desirable that the design takes this into consideration.

However, since the conventional core support frame is rigidly fixed, the above considerations are not taken.

The present invention has been made based on the above circumstances, and it suppresses thermal deformation of a group of core components to a minimum, absorbs collision energy when colliding with a group of core components, reduces collision force, and The object of the present invention is to obtain a core support frame device that can reduce the overall collision force and obtain a vibration damping effect.

In the present invention, the above object is achieved by supporting the core support frame on the inner wall of the reactor vessel via a friction damper.

The invention will be explained in detail below with reference to the drawings. In FIGS. 1 and 2, core components 1 are supported in a predetermined position by inserting their lower ends into through-holes in a support plate 2 provided at the bottom of the core, and the outer periphery of the component group formed by these components is , core support frames 3, 3 are provided to surround the component group at the upper and intermediate parts of the component group, and the support frame 3 is connected to the inner wall of the reactor vessel 5 via a friction damper 4, the details of which are shown in FIG. installed. Note that 6 in the figure indicates a heat shield plate provided surrounding the component group.

In FIG. 3, a support member 7 protruding from the support frame 3 toward the inner wall of the furnace vessel 5 is cylindrical and has a cylindrical shape.
The spring cylinder 7a has an open end on the inner wall side, and a shaft rod 7b that is concentric with the spring cylinder 7a and has a circular head 7c at the end that protrudes from the open end.
On the other hand, a support member 8 attached to the inner wall of the container 5
has a spring cylinder 8a that fits into the spring cylinder 7a, and a stopper chamber 8c connected to the spring cylinder via a partition wall 8b having a through hole with a diameter smaller than that of the circular head 7c. The circular head 7c is the stopper chamber 8
It is housed in c. Further, the tip of the shaft rod 7b is threaded, and the length of the shaft rod 8b is adjusted by a nut-shaped circular head 7c. Further, a ring spring 9 is engaged with the shaft rod 7b. The ring spring 9 is constructed by combining an inner ring 9a having an abacus bead-shaped outer peripheral surface and an outer ring 9b having inverted conical surfaces on both end faces corresponding to the inclined surfaces of the inner ring 9a. These inclined surfaces and inverted conical surfaces constitute frictional sliding surfaces that slide against each other when the ring spring 9 contracts. Note that the number, combination, and characteristics of the friction dampers 4 having the above configuration are appropriately selected, and the supporting steel of the core support frame 3 is set to be sufficient to suppress thermal deformation of the core components during normal reactor operation. . Further, the length of the friction damper and the initial tension applied to the shaft rod 7b are appropriately adjusted by the circular head 7c.

The friction damper 4 described above operates as follows.

That is, when a force (compressive force) is applied in a direction that causes the spring tubes 7a and 8a to approach each other, the inner ring 9a fits into the outer ring 9b, the inner ring 9a is compressed, and the outer ring 9
b is expanded. At this time, each ring slides along the inclined surface, and a frictional force is generated due to friction, and a restoring force as a spring is generated by the restoring force against the compression of the inner ring 9a and the expansion of the outer ring 9b. The load characteristic of the ring spring 9 at this time shows a hysteresis loop as shown in FIG. 4, and energy corresponding to the area within the loop is absorbed.

The core support frame 3 of the present invention supported on the inner wall of the vessel 5 via the friction damper 4 as described above operates as follows. During an earthquake, when the core component group begins to vibrate and the component group 1 in contact with the support frame collides with the core support frame 3, a load acts on the ring spring 9 in the friction damper 4, and the ring spring 9 In the manner described, the impact energy is absorbed and an appropriate restoring force is generated. While the core components are vibrating, the above-mentioned absorption of collision energy and generation of restoring force are repeated, reducing the collision energy at the time of the collision, reducing the vibration of the core components, and reducing the excessive force of the core components. It is possible to prevent the occurrence of severe collision force.

As described above, the core support frame of the present invention can suppress thermal deformation of the core component group during normal operation of a nuclear reactor, and also reduce the collision force between the components and the support frame in the event of an earthquake. It is possible to reduce the amount of vibration absorbed by the shock absorbing effect caused by the expansion and contraction of the springs and the vibration damping effect caused by the sliding contact between the frictional sliding surfaces between the springs, thereby improving the seismic resistance within the core. In addition, since vibration is damped by the friction between each spring without the need for a special damping device, the structure is simple, the core is compact, and there is no need for an intervening device between the core components and the support frame. It is advantageous to set up

The friction damper using a ring spring as shown in the example is relatively small and has high rigidity, and has good energy absorption efficiency, so it has much greater damping than a viscous damper of similar size. Effects can be obtained. This is particularly effective against collision loads where loads are applied all at once. Also, since it is made of metal, it has excellent heat resistance. Furthermore, desired characteristics can be obtained by combining the inner ring and outer ring. Moreover, since the structure is simple, maintenance is easy. Therefore, friction dampers using ring springs are ideal for use inside high-temperature reactor cores, but
A friction damper using a disc spring instead of a ring spring may be used. Additionally, the present invention may be applied to nuclear reactors other than the illustrated fast breeder.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an embodiment of the present invention, Fig. 2 is a longitudinal sectional view thereof, Fig. 3 is a sectional view of the friction damper, and Fig. 4 is a characteristic diagram of load and deflection of the friction damper. . 3...Core support frame, 4...Friction damper, 5...Inner wall of reactor vessel, 7, 8...Support member, 7a, 8a...Spring cylinder,
7b... Axis rod, 7c... Head, 8b... Partition wall, 8c... Stopper chamber, 9a, 9b... Ring spring.

Claims (1)

[Claims] 1. A reactor core support frame that surrounds a group of core components, and a friction damper that fixes the core support frame to the inner wall of the reactor vessel and has the following structural requirements. Nuclear reactor core support frame device. a: a first support member protruding from the core support frame toward the inner wall of the reactor vessel; b: a second support member provided on the inner wall of the vessel and facing the first support member; c: the first and second supports. a plurality of springs interposed between the support members; d a friction sliding surface formed between the plurality of springs and slidingly contacted by contraction of these springs;